package com.tsd.core.utils;


import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Random;

/**
 * 随机数字工具类，用于验证码
 * 先Instance
 *
 * @author Hillpool
 */
public class RandomNumUtil {
    // 图像
    private ByteArrayInputStream image;
    // 验证码
    private String str;

    private RandomNumUtil() {
        init();
    }

    /*
     * 取得验证码图片
     */
    public ByteArrayInputStream getImage() {
        return this.image;
    }

    /*
     * 取得图片的验证码
     */
    public String getString() {
        return this.str;
    }

    /**
     * 初始化
     */
    private void init() {
        // 在内存中创建图象
        int width = 90, height = 38;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        // 获取图形上下文
        Graphics g = image.getGraphics();
        // 生成随机类
        Random random = new Random();
        // 设定背景色
        g.setColor(getRandColor(250, 255));
        g.fillRect(0, 0, width, height);
        // 设定字体
        g.setFont(new Font("Times New Roman", Font.PLAIN, 36));
        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(1, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(150);
            int yl = random.nextInt(150);
            g.drawLine(xl, y + x, y, y + yl);
        }
        // 取随机产生的认证码(6位数字)
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(random.nextInt(10));
            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(180), 20 + random
                    .nextInt(180), 20 + random.nextInt(180)));
            // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand, 13 * i + 18, 30);
        }
        // 赋值验证码
        this.str = sRand;

        // 图象生效
        g.dispose();
        ByteArrayInputStream input = null;
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        try {
            ImageOutputStream imageOut = ImageIO
                    .createImageOutputStream(output);
            ImageIO.write(image, "JPEG", imageOut);
            imageOut.close();
            input = new ByteArrayInputStream(output.toByteArray());
        } catch (Exception e) {
            System.out.println("验证码图片产生出现错误：" + e);
        }

        /* 赋值图像 */
        this.image = input;
    }

    /**
     * 给定范围获得随机颜色
     *
     * @param fc
     * @param bc
     * @return
     */
    private Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
}
